In Subsurf on a crown. How can I smooth some edges and keep others sharp?, there's an answer suggesting to use crease, which I agree is a good way to solve the problem.

But then, there's a comment telling "nice, but instead of crease, which hurts, maybe you can finish by some bevels..."

Why creases are (at least in that context) bad?

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    $\begingroup$ Crease creates perfectly sharp angle which might be undesirable (it can be set to 0.5 or something but in some condtions it will not get rid off of all artifacts on smoothed surface). However it is not always the case; I would tell that it depends on the model and its purpose (realistic / non realistic, far away / close etc). $\endgroup$ – Mr Zak Feb 26 '19 at 0:13
  • $\begingroup$ Probably because they can cause pinching and uneven density, but they are not all bad, they are probably OK under most situations $\endgroup$ – Duarte Farrajota Ramos Feb 26 '19 at 1:14
  • $\begingroup$ Edge crease, at level 1 subdiv, isn't going to be much different than a bevel. Yes, it can cause some pinching, but so can a bevel. But you can't tune your edge crease for each level of subdiv. Using subdiv2+, your edge crease is going to lead to wasted verts that are all bunched up. Bevel & subdiv1+ will lead to less vert "wastage." But it's not a big deal. Most of the time, there are more important things to worry about. $\endgroup$ – Nathan Feb 26 '19 at 6:13
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    $\begingroup$ I am the author of this phrase, I personally think it's better not to use a trick like crease because you don't learn how to model properly, you don't learn how to fix the kind of problems like sharping, pinching, etc... you may cross problem that you won't be able to fix if you haven't been confronted before, plus you may need to export your object and it may not work on other 3D apps... but it's my own opinion, I'm still a post-noob and I can be proved wrong :)) $\endgroup$ – moonboots Feb 26 '19 at 10:51
  • $\begingroup$ @moonboots me too.. permanently post-noob .. but I've come to think using Crease is just fine, if you know what it's doing, ( and if it's left live, unapplied, any engines you may be exporting to understand it, too). $\endgroup$ – Robin Betts Feb 26 '19 at 11:56

Oops, partly my bad.. I'll go back to edit the answer..

'Crease' acts in combination with Catmull-Clark subdivision / Open Subdiv - it modifies the extent to which edges are 'pinned', preventing them from being interpolated, (and therefore moved/smoothed) by the subdivision algorithm. In your original question, it prevents the points of your crown from being rounded by subdivision.

There's nothing wrong with using it, but in this case, on its own, it produces a result like the one on the left, below. As you can see, there are still smoothing artifacts.

The one on the right, after applying the solidify and its creases, futhermore puts a bevel on the rims, peaks and troughs. It's much improved, in the way I took moonboots to mean.

enter image description here

Without a crease holding some of the edges against interpolation by subdivision, trying to use a bevel on its own (before subdivision) to harden edges, can give rise to this sort of problem at concave junctions:

enter image description here

..where the interpolation 'leapfrogs' the vertex positions it is smoothing, jumping into empty space.

So, in this case, one way out is to bevel after creasing and subdivision, as on the right in the first picture.


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